Apparatus for preparing plates for etching



April 1944- L SCARZE LLO ETAL 2,347,511

APPARATUS FOR PREPARING PLATES FOR ETCHIHG Filed Dec. 27, 1941 4Sheets-Sheet 1 A YTORNEY April L. SCARZELLO arm. 2,347,511

. mums FOR PREPARING PLATES FOR momma Filed Dec. 27,1941 4.Sheets-Shet zFIC3.2.

I an

ATTORNEY INVENTORS April 1944- L scARzELLo El AL 34 5 APPARATUS FORPREPARING PLATES FOR ETGHING filed Dec. 27, 1941 4 Sheets-Sheet 3 April25, 1944. SCARZELLO ETAL 2 APPARATUS FOR PREPARING PLATES FOR ETCHINGFiled Dec. 27, 1941 4 Sheets-Sheet 4 Patented Apr. 25, 1944 guru UNITEDSTATES ?ATENT OFFlQE APPARATUS son PREPARING PLATES FOR ETCHINGApplication December 27, 1941, Serial No. 424,616

2 Claims.

This invention relates generally to etching processes and apparatus andis more especially directed to a method and apparatus for treatingplates for the removal therefrom of the superfluous resist, followingthe inking or design imprinting and resist applying steps in the platepreparation, and preliminary to the heating or so-called baking of theplates, in the process of conditioning them for the etching operation.

At present, it is the general practice, following the imprinting of adesign upon a plate and the application of the resist thereto, to forman acid-proof protective coating for the design, to remove thesuperfluous resist by hand brushing the plate with a camels hair brush.However, this method does not insure entirely satisfactory results,since it is impossible to completely remove such resist as may have beendeposited upon the surface of the plate that is to be etched and itfrequently happens that in the manipulation of the brush across theportion of the plate carrying the design, that some of the overlyingprotective coating thereof is loosened and brushed away, with the resultthat the border or other portions of the design may be improperlyetched, while those parts of the plate from which the resist has notbeen entirely removed will be sufficiently tched. Also, it is notunusual for a plate to have a film of oil thereon, as a result offorming or handling, which further contributes to the impossibility ofthoroughly removing the superfluous resist from the plate surface by theuse of a hand brush. While, customarily, the plate may be wiped, in anattempt to free it of the oil film, all traces thereof cannot be removedby Wiping and, in consequence, there is a tendency of the resistparticles to adhere to the oily surface, which, obviously, increases :helikelihood that the results will be unsatisfaccry.

The primary object of this invention is to provide a method andapparatus for effecting complete removal of the superfluous resist froma plate on which the resist has been deposited by dusting or otherwiseto form an acid-proof protective coating for a design imprinted thereon,whereby unsatisfactory results, such as flow from the use of theaforementioned current inefficient methods will be entirely eliminated,our

matter which may have accumulated thereon, in

hand ing, or otherwise, without detrim'entally aifecting any portion ofthe design-protecting: coating, so that etched product may be producedbythe use of our invention which will possess a uniformly high degree ofexcellence not'heretofore attainable.

More specifically, it is the object of this invention to provide amethod and means, whereby the removal of the excess or superfluousresist adhering to a plate, as aforesaid, may be auto-' maticallyeffected to insure not only complete removal of such superfluous resist;but to attain this desirable result in a manner to protect that portionof the resist which is in adherence with the design imprint againstpossible partial disintegration, as may occur in existing methods. Thisobjective is attained by progressingthe resist treated plate in acontrolled path, through a series of zones wherein it is subjected tofluid action, the fluid, in certain of the zones, coacting with meansadapted to make physical contact with the plates to supplement theaction of the fluid in freeing the plate of all superfluous resist andother non-essential matter which may have been deposited thereon inprior processing;

It is also an object of this invention to provide a method and apparatushaving the aforesaid 'nism for delivering it to the baking apparatus,

thereby eliminating handling of the plate between these successivestages of its processing,

and possible surface marring which might result therefrom.

' Other objectives of our invention and advantages flowing from thepracticing of the same will become manifest as the description proceeds.

For the purposes or this disclosure, we have" elected to show anddescribe a preferred form of apparatus. whereby the steps of our methodmay he efficiently practiced for the attainment of the hereinbeforerecited objectives. However, as will be clearly understood, the steps ofour method may be performed by the utilization of other forms ofapparatus, which may diiier from that herein and described, in variousWays,

within the spirit and scope of the invention, as-

defined by the appended claims.

In the drawings:

Figure l is a top plan View of my preferred form of apparatus. Figure .2a side elevation looking in the direction of the arrows 22 of Figure 1.Figure 3 is a longitudinal section of the apparatus, taken on the line3-3 of Figure l.

Figure 4 is a transverse vertical section on the line 44 of Figure 1.

Figure 5 is an elevational view, partly in sec tion, taken on the line5-5 of Figure 1, of the air-blast unit of my apparatus and the mechanism for reciprocating it transversely of the conveyor.

Figure 6 is a view in perspective, of the reciprocating brush of theapparatus shown in Figure 1; and

Figure 7 is a perspective of a fragment of the air-blast unitillustrated in Figure 5.

Referring now to the drawings in detail, in which like characters ofreference are employed to designate similar parts in the several views,the apparatus embodies an endless conveyor l0, formed of reticulatedwire fabric or screening, as at I supported between the link chains l2and I3, which transverse the sprockets I4 and 5 mounted on the shafts l6and I! disposed transversely of the apparatus and having bearings in theside forming members l8 and L! of the apparatus. As herein shown, theseside members embody supporting feet or legs 29 and 2|, which are formedto receive and support a tank 22 beneath the conveyor, the length andwidth of which correspond approximately to the overall length and widthof the conveyor, for the purposes, which hereinafter, will becomeapparent.

Supported between the end extensions la and |9a of the aforesaid sidemembers of the apparatus, is a table 23 in the plane of the uppersurface of the conveyor, for the reception of the plates indicated at Pwhich are to be placed upon the conveyor for treatment for the removalof the superfluous resist, the plates being entered upon the conveyor,in a hand operation, beneath the transverse end-forming member 24,spanning the conveyor at the plate-entering end thereof. Behind thismember 24 are located in appropriately spaced relation, means forspraying a slightly alkaline solution upon the plates carried by theconveyor, as they pass therebeneath. In the present embodiment, thesemeans comprise the pipes or tubes 25 and 26, supported between the sidemembers of the apparatus and spanning the conveyor, which are eachprovided with a series of nozzles or jets 21 and 28 disposed at an angleto direct the liquid discharged therefrom toward and downwardly upon theadvancing plate, the pipes 25 and 26 being respectively connected, as at29 and 3D, to the take off 2|, from the pump 32, driven by the motor 34,through the shaft 33. The pump draws the liquid which is delivered tothe pipes 25 and 26, for discharge from their respective sets ofnozzles, from said tank 22, through the line pipe 35 which is disposedparallel to and external of the side l8 of the apparatus and isconnected to the end of the tank or reservoir, adjacent the basethereof, through the screened outlet 22a and the branch or lateralpiping 35a, parallel to the end of the tank, as shown in Figs. 3 and 4.

As the plate P carried by the conveyor, passes beneath and leaves thezone of the spraying head 26, it is next subjected to the action of acamels hair brush, also connected to the pump take off l 3|, mounted forreciprocatory movement, transversely of the conveyor. This brushincludes a head or body-portion 36, having internal spray passages orconduits, with which the tube 3'! carried thereby communicates, thelatter being connectable by the flexible tubing 38 to the pump take off3|, as stated, by the T 39. A rod 40, fixed latter from the complementalbearing end Me of the arm 4|, dependent from the slide 42, for relativeadjustment, through the medium of the set screw 42b. The slide 42 isreciprocable on the squared shaft 43, mounted in the bearing portions 44and 45 of the brackets 46 and 41, bolted to the side members of theapparatus, as at 48 and 49. As will be noted, the longitudinal axis ofthe brush head, as clearly shown in Fig. l, is disposed at an angle ofapproximately 45 to the median line of the conveyor, so that as thebrush is reciprocated transversely of the conveyor, as hereinafterdescribed, the brush will move across th plate P at an angle to itsdirection of travel, to cause the vertically dependent hair of thebrush, indicated at 36a, to contact with and pass over the plate in awiping sweep, the liquid emitted from the spray passages of the brushhead into the hair flowing therethrough to discharge upon the plate,also serving to keep the brush clean and continuously maintain it in asubstantially vertical position, relatively to the plate surface overwhich it is passing, in brushing contact, as aforesaid.

Appropriately spaced behind the reciprocating brush 35 is a secondcamels hair brush of a length corresponding to the width of theconveyor, the body-portion 50 thereof, from which the hair 50a isvertically dependent, being mounted within an embracing spray head 5|,fixedly supported between the side members l8 and IQ of the apparatus,transversely of the conveyor, and connected to the pump riser or takeoff 3|, as by the pipe 52. This spray head 5|, as shown (see Fig. 3) isformed to direct the liquid discharge downwardly toward and upon theopposite faces of the brush, as at 53 and 54, and. similarly to theliquid discharged from the brush 3B, and at the same time cleanses thebrush and maintains the hair substantially vertical, as the plate passesbeneath the brush and is subjected to the action of the hair in contacttherewith and the liquid discharged thereon.

As pointed out, the spray heads 25 and 26,

the reciprocating brush 36 and the spray head 5| embracing thestationary brush 50, 50a, are each connected to the pump 32 whichdelivers thereto the alkaline solution drawn from the reservoir or tank22, for emission from the respective units in the performance of theseveral steps of my process of treating the plate, as hereinafter ex- 7plained, the solution draining through the conto the brush head orbody-portion supports the 76 veyor into the tank, so that, in effect,continuous circulation of the solution is maintained during theoperation of the apparatus, the tank serving asthe source of supply.

Positioned behind the stationary brush 50, 50a, is another spray head55, which similarly to the spray heads 25 and. 26, is disposedtransversely of the apparatus and fixed to the side members l8 and I9,which also is provided with nozzles or jets, indicated at 56, also setat an angle to direct a discharge of clear water toward and upontheadvancing plate, as it moves from the zone of the aforesaid stationarybrush. This spray head 55 is connected to a source of clear watersupply, as by the pipe or conduit 51. The water issuing from the nozzlesor jets 56, flushes the plate as itv passes through the effective zoneof the nozzle discharge, to remove therefrom any brush hairs or othermatter there may have adhered thereto, during the passage of the platebeneath the contacting brushes, and any traces of the alkaline solutionthat may remain on the plate, the water draining through the conveyorinto the tank 22, to mix with the solution therein. To prevent unduedilution of the tank solution, by

the water discharged from the spray head jets cludes a head 64 carryingtwo laterally spaced.

parallel nozzle sections 60 and BI with their axes disposed transverselyof the conveyor, each of which is provided with a series of jets oroutlets, indicated at E2 and 63, so located that the air,

streams impinge upon the advancing plate at an angle of approximately 45to the surface thereof, the head including an upright piece of tubing,fixed thereto, as at 65, which is connectable by the flexible tubing 66to the conduit 61. leading to an air compressor or other source of airsupply. The tubing 66 is adapted to be entered in the bearing end 6841of the rod 68, the latter being mounted in the bearing portion 89 of thearm 19 dependent from the slide 1| reciprocable upon the shaft 72 fixedbetween suitable brackets 12a and 12b bolted to the apparatus, similarlyto the brackets 48 and 47. To admit of the adjustment of the air devicerelative to the surface upon which the air streams emitted thereby areto be effective, the tubing 56 is axially and rotatably adjustablewithin the complemental bearing 63a, a set screw 73 being provided tolock the tubing in the desired position of adjustment therein.Similarly, the rod 68 is adjustable within the bearing with which it isengaged, for adjustment longitudinally of the conveyor, to permit ofproper spacing of the air device between the adjacent spray head and thetake off end of the conveyor for efficient performance, the rod beinglocked in adjusted position with the bearing sleeve by the set screw 13.

A gear box of housing 16 is supported by a bracket 1'5 fixed to the sidemember IQ of the apparatus, which encloses a suitable reduction geartrain (not shown) adapted to be driven from the electric motor '1?mounted on the bracket 13, which is bolted to the apparatus. The motortorque is transmitted to the drive shaft of the gear assembly, throughthe belt 3!, travelling upon the pulley l9 keyed to such shaft 85.. Ashaft 82, which is journaled in bearings 83 and 8A, asg sociated withthe aforesaid brackets 45 and 13, embodies a worm gear (not shown)adapted to mesh with the driving gear of said gear train, suitablebearings for said shaft 82, in juxtaposition to said worm, beingprovided in the gear case 15, through which the shaft extends, shown inFig. 1.

Fixed to the end of the shaft 82, adjacent the bearing 84, is a crank 86connected by a link 8'! to the slide 42, from which the brush 35 isde'-. pendently supported, as explained, while keyed to the other end ofsaid shaft is a similar crank 88, which, likewise, is connected by alink 85 to the slide H which carries the air discharge device. As willbe manifest, the rotation of the shaft 82 in a clockwise direction, (asviewed in Fig. 4) as it is driven from the aforesaid gear as; sembly,will produce reciprocatory movement of the slides 42 and H on theirrespective guide shafts 43 and 2, with the result that the brush ance ofthat final step of the process.

36 and the air discharge device carried by said slides 42 and H willtravel to and fro across the conveyor, in relatively alternatedirections, because of the diametrically opposite disposition of thecranks 86 and 88 on the shaft 82, which, of course, also serves tobalance the shaft action, with the concomitant advantages,

In practicing the steps of our method of removing superfluous resistfrom a plate, in the processing of such plate for etching, byautomatically functioning means, as embodied in the form of apparatusjust described, the plate P is transferred from the table 23 to theconveyor by hand, as explained, the subsequent steps being automaticallyperformed as the plate progresses through the apparatus, so that allfurther handling of the plate to and through the baking stage of theprocessing is entirely eliminated, as will become apparent. Now,'as theconveyor ill traverses the sprockets l4 and IS, the plate is advancedthrough the apparatus in a continuing operation for treatment in aseries of spaced zones, the first of which is that in which the sprayhead 25 is efiective, the surface of the plate being exposed to theaction of the alkaline solution discharged from the nozzles thereof,beneath which it passes to receive the angularly impinging liquid jetsdischarged from the nozzles 28 of the spray head 26. The pressure of theliquid issuing from the nozzles of these two spray heads is sufficientto force or drive off the resist from the non-imprinted portion of theplate, but not strong enough to separate or produce disintegration ofthe resist that is in ad herence with the inked design, with a resultthat the greater part of the superfluous resist, especially that whichmay be readily flushed off, is removed in the first two zones throughwhich the plate travels.

-As the plate moves beneath the reciprocating brush 35, the end of thebrush makes physical contact therewith and passes over the surfacethereof in a wiping action, as heretofore explained, the action of thebrush, combined with that of the liquid discharged through the brushserving to loosen and remove such particles of the resist as mightadhere to the plate surface because of a slight oil film that usuallyremains on the plate from previous treatment. The alkalinity of thesolution in cooperation with the wiping action of the brush contributesto clearingthe oil film from the plate surface which is essential inattaining action of the etching solution, when the plate is ready forthe perform- In this connection it may be pointed out the effectivenessof brush is enhanced, since both the plate and brush are in motion, thelatter moving across in a path at an angle of approximately 45 to thepath of movement of the plate. While the brush action is sufiicient toloosen resist still adhering to the plate surface, following theflushing to which the plate is subjected by the spray heads 25 and 28,the imprint upon the plate has sufficient adhesive qualities to maintainthe overlying protective coating completely intact, against suchpressure as may be applied thereto by the brush 36 in passing thereover.

As the plate progresses from the zone of the brush 35, it is subjectedto the action of the fixed brush 50, a, the hair tufts of which actvertically of the plate moving beneath it, the eiiect here, of course,differing from that of the wiping action of the brush 35, since theplate only moves with relation to the brush, the effective action beingsolely dependent upon theliquid flow through the brush and themaintenance of the brush hair in a substantially constant verticalposition. On passing from the area of the stationary brush 50, 59a, theplate enters the zone of the spray head 55, the fresh wateremitted fromthe nozzles 56, flushing the plate surface, without of course, affectingin any way the bond of the resist with the imprinted design, andfloating therefrom any traces of alkaline solution and such particles ofresist that may still remain on the plate surface, together with anyother foreign matter that may have accidentally been deposited on theplate, as hairs that may have become loosened from one or the other ofthe brushes,

The thoroughly washed plate now moves into the air zone of theapparatus, being subjected to the effect of the impinging air streamsdirected tangentially to the plate surface from the aforementioned airdevice, the air spreading over the surface to displace the majorportion, if not all of themoisture which may remain on the platesurface, so as to condition it for transfer to the baking stage of theplate processing in a fairly dry state,

As the plate leaves the zone of the air device, it is advanced beyondthe rear end of the conveyor to be engaged by the take-off roll 90, theflexible fins of which frictionally engage the underside of the plateand urge it toward the train of rollers 91 which move it to a positionto be picked up by the conveyor 92, whereby it is delivered to thebaking oven, (not shown), the

movement of the two conveyors It] and 92 being synchronized, theconveyor la, in the present showing being driven from the conveyor 92,through the medium of a chain lta in meshing engagement with thesprockets 93 and 94,

sprocket 93 being mounted on the shaft 95 of the conveyor 92, while thesprocket 94 is keyed to the shaft it of the apparatus conveyor {0. Thetake off roller 90 and the rollers 9| associated therewith are drivenfrom the other end of the shaft l6 of the apparatus, through the mediumof the link belts 96 and 91 in engagement with suitable sprockets onsaid rollers. As will be obvious, the conveyor It] may be independentlydriven, or may drive the conveyor 92, and the drive for the take-- offroll and the transfer rollers may differ from that herein shown.

As the plate passes through the apparatus on. the conveyor ID, thealkaline solution discharged from the units connected to the pump line3|,- and the water-issuinglfromthe spray head 55 percolate through the'meshesof the conveyor,

carrying into the tank 22 the resist and other matter that has beenremoved from the plate in its transit through the apparatus.

floats to the top of the tank solution and ultimately is discharged fromthe outlet 22b located at the forward end of the tank, beneath the table23 of the apparatus. As heretofore explained, the requisite degree ofalkalinity of the tank solution is maintained, by introducing an ammoniasolution thereto, from time to time, to offset the diluting effect ofthe water draining into the tank from the spray head 55.

From the foregoing, it will be manifest that the steps of my method areautomatically performed in a sequence, involving in each instance theexposure of the plate surface to fluid action, which in certain of thesteps is supplemented by mechanical means effective upon the plate Themat-' ter, some of which may be in a colloidal state,

surface, under the influence of the coacting fluid to remove therefromall matter that is extraneous to the protection of the imprinted design,so that the surface of the plate that is to be etched is devoid of anyoily film, scale or other deposit which will tend to arrest the actionof the etchingacid. Further, by utilizing our invention, the integrityof the imprinted design is insured against the action of the etchingacid, since the resist coating thereof is in no wise affected, as theplate progresses through an apparatus for treatment, according to ourmethod, even in the border area of the design, where the adherencebetween the ink and the resist applied to the design may not be so greatas elsewhere.

While we have described our invention, as it may be practiced inconjunction with apparatus of the type herein shown, it will beunderstood that the steps thereof may be carried out by other means andthe sequence of the steps may vary, the apparatus shown and describedobviously, being subject to changes in structure and mode of assemblyand cooperation of the components thereof, to meet specific requirementsof production and use, all of which fall within-the spirit and scope ofour invention.

We claim:

1. An apparatus for automatically removing superfluous resist from thesurface of a plate, as a step in a process for preparing such plate foretching, including a conveyor adapted to receive the plate and transportit in a continuing movement through said apparatus, a pair of sprayheads supported above said conveyor, in spaced relationship, havingnozzles adapted to direct a surface in the path of wiping movement of.the, brush thereover, in theremoval of the super fluous'resist, asecond brush fixedly supported from said apparatus disposedtransverselyof said conveyor, in rearwardly spaced relation to saidreciprocating. brush device, means for saturating said fixed brush withliquid to co-act with said fixed brush as the plate passes beneath saidlatter brush in contact therewith, means for connecting. said sprayheads, said reciprocating brush device and. said fixed brush to a sourceof liquid.

supply,a .spray head'in rearwardly spaced rela,-.

tion to said fixed brush, an air discharge device supported rearwardlyof said liquid-emitting spray head adapted to discharge air upon thesurface of the cleansed plate for drying, andmeans for reciprocatingsaid airdischarge device transversely of said conveyor for vaporizingthe;

moisture from said plate. Y

2. An apparatus for automatically removing superfluou resist from thesurface of a plate,-

as a step in a process for preparing such plate-for etching, including aconveyor adapted to receive the plate and transport it through said,appa -cratus in a continuing movement, spray heads fordirecting analkaline solution upon said plate.

during the progression of the plate on said conveyor, a liquid saturatedbrush supported above said conveyor in rearwardly spaced relation-tosaid spray heads, means for reciprocating said brush transversely ofsaid conveyor to wipingly traverse said plate, whereby the saturatingliquid shed by said brush in its wiping contact with the plate willflush the surface of said plate simultaneously with the movement of thebrush thereover, a second brush fixedly supported from said apparatusand extending transversely across said conveyor rearwardly of said firstbrush adapted to flexibly contact with the plate passing thereunder,means for subjecting the brushed plate to the cleansing action of waterdirected thereupon while said plate progresses on the conveyor, and areciprocable air discharge device for evaporating the moisture from saidplate.

LEO SCARZELLO. JOSEPH NOWATIUS. MARTIN BULIN.

